J Korean Soc Radiol.  2016 Jul;75(1):1-11. 10.3348/jksr.2016.75.1.1.

CT Findings of Benign Omental Lesions Following Abdominal Cancer Surgery

• Lee SY
• Kim DW
• Cho JH
• Kwon HJ
• Ha DH
• Oh JY

• KMID: 2327360
• DOI: http://doi.org/10.3348/jksr.2016.75.1.1

Abstract

The greater omentum is the largest peritoneal fold and can be the origin of primary pathologic conditions, as well as a boundary and conduit for disease processes. Most diseases involving the omentum manifest with nonspecific and overlapping features on computed tomography (CT). In particular, varying benign disease processes of traumatic, inflammatory, vascular, or systemic origin can occur in the omentum during the follow-up period after surgery for intra-abdominal malignancy. It can be challenging for radiologists due to various spectrum of CT findings. Thus, we reviewed the CT findings of various benign omental lesions after surgery for intra-abdominal malignancy.

MeSH Terms

Abdomen
Follow-Up Studies
Omentum

Figure

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  Fig. 1 Illustrations show sagittal anatomy of abdominal cavity. D = duodenum, GCL = gastrocolic ligament, GHL = gastrohepatic ligament, GO = greater omentum, LS = lesser sac, P = pancreas, SB = small bowel, Sto = stomach, TC = transverse colon

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  Fig. 2 Omental contusion in a 74-year-old man who underwent low anterior resection for rectal cancer. A. Preoperative CT reveals no omental lesion. B. Contrast-enhanced CT scan obtained 15 days after operation shows ill-defined haziness (arrows) in the right side of the greater omentum. C. Follow-up CT at 2 months after operation shows resolution of the omental lesions.

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  Fig. 3 Omental hematoma in a 57-year-old woman after laparoscopic biopsy for pancreatic cancer. A. Non-contrast CT scan shows high density lesion (arrows) in the greater omentum. The metallic stent is inserted in the CBD. B. Coronal reformatted image reveals ill-defined high density lesion (arrows) in the left side of the greater omentum CBD = common bile duct

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  Fig. 4 A 53-year-old man with heterotopic omental ossification after low anterior resection for rectal cancer 2 months ago. A, B. Axial CT scans show ossified mass like lesion (arrows) in the greater omentum just beneath the incision skin line. C. Coronal reformatted image shows ossified lesion (arrows) along the greater omentum.

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  Fig. 5 Postoperative omental abscess in a 59-year-old man who underwent total pancreatectomy and splenectomy for intraductal papillary neoplasm of the pancreas. A. Postoperative CT scan obtained 5 months after surgery shows loculated fluid density lesion with thick enhancing wall (arrow) in the greater omentum. The stomach is compressed by the abscess. B. Coronal reformatted image reveals abscess cavity (arrow) in the greater omentum.

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  Fig. 6 Gossypiboma in a 53-year-old woman who underwent total abdominal hysterectomy for cervical cancer 3 months ago. A. Non-contrast CT scan shows large cystic mass with high density of wavy appearance (arrows) and mottled air bubbles (arrowheads) in the greater omentum. B, C. Arterial (B) and portal (C) phase of contrast-enhanced CT scans reveal thick capsular enhancement of the lesion (arrows).

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  Fig. 7 A 50-year-old woman with omental panniculitis after radical total gastrectomy for gastric cancer. A. Contrast-enhanced CT scan obtained 3 years after operation shows soft tissue density mass like lesion (arrows) in the right side of the greater omentum. B. Coronal reformatted CT image reveals well-defined mass like lesion with surrounding fatty infiltration (arrows) in the greater omentum. It was pathologically confirmed to omental panniculitis by right hemicolectomy.

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  Fig. 8 A 60-year-old man with omental lesion related to pancreatitis who underwent distal pancreatectomy and splenectomy for splenic lymphoma. Contrast-enhanced CT scans obtained 1 month after operation show well defined, encapsulated fluid collection with air bubbles in peripancreatic area (arrows). According to Atlanta classification, these findings are suggestive of walled-off necrosis. Continuity (arrowheads) between omental lesion (blank arrows) and peripancreatic walled-off necrosis is observed.

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  Fig. 9 Schematic figure of the omentum-preserving gastrectomy. Dotted line indicates the incision line of the greater omentum during omentum preserving operation.

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  Fig. 10 A 55-year-old woman with omental infarction who underwent subtotal gastrectomy for gastric cancer. A. Contrast-enhanced CT scan obtained 2 months after operation shows ill-defined area of increased density (arrows) in the greater omentum. B, C. Follow-up CT images at 6 months (B) and 24 months (C) show smaller, fat density lesion with rim enhancement (arrows). The CT appearance of omental infarction was changed from type 1 to type 2 omental infarction.

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  Fig. 11 Postoperative omental edema in a 80-year-old man with underlying liver cirrhosis after subtotal gastrectomy for gastric cancer. A. Contrast-enhanced CT scan obtained 10 days after surgery shows diffuse haziness and streaky increased fatty strands at the greater omentum (arrows), small bowel mesentery and retroperitoneum (blank arrows). Ascites is also noted in right subhepatic space (arrowhead). B. Follow-up CT scan after 6 months shows complete resolution of omental edema with improvement of underlying liver cirrhosis. The edema of small bowel mesentery and retroperitoneum was also resolved.

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